Fieldwork Skills » Fieldwork Equipment - Clinometer

What you'll learn this session

Study time: 30 minutes

What a clinometer is and its purpose in geographical fieldwork
How to use a clinometer to measure slopes and gradients
Different types of clinometers available for fieldwork
How to record and interpret clinometer data
Common errors in clinometer usage and how to avoid them
Practical applications of clinometer measurements in geographical studies

Introduction to Clinometers in Geographical Fieldwork

When studying landscapes, rivers, slopes and other geographical features, measuring angles and gradients is essential. A clinometer is one of the most important tools in a geographer's fieldwork kit, allowing you to measure the angle or slope of landforms accurately.

Key Definitions:

Clinometer: A handheld instrument used to measure angles of slope, elevation, or depression.
Gradient: The degree of steepness of a slope, usually expressed as a ratio, percentage, or angle.
Angle of slope: The angle between a sloping surface and the horizontal plane.
Degrees: The unit used to measure angles (°), with a complete circle being 360°.

Why Measure Slopes?

Understanding slope angles helps geographers explain numerous geographical processes including:

Rates of soil erosion
Land stability and risk of landslides
River velocity and energy
Drainage patterns
Vegetation distribution
Human settlement patterns and land use

Types of Clinometers

There are several types of clinometers available for fieldwork, each with its own advantages and limitations:

🔩 Traditional Clinometer

A basic handheld device with a weighted pointer that hangs vertically due to gravity. When you sight along the top of the clinometer, the pointer indicates the angle on a scale.

📱 Digital Clinometer

Modern electronic devices that give precise digital readings. Many smartphones now have clinometer apps that use the device's built-in accelerometer to measure angles.

🔮 Abney Level

A more sophisticated type of clinometer that combines a sighting tube with a spirit level and protractor. It allows for more precise measurements over longer distances.

🌍 Homemade Clinometer

Can be constructed using a protractor, string and weight (like a washer). These are inexpensive alternatives that work on the same principle as traditional clinometers.

How to Use a Clinometer

Using a clinometer properly requires practice but follows a straightforward process:

1️⃣ Preparation

Stand at the bottom of the slope you want to measure. If working in pairs (recommended), one person should stand at the top of the slope.

2️⃣ Sighting

Hold the clinometer at eye level and look through the sighting tube or along the top edge. Aim at a point that's at the same height as your eye level at the top of the slope.

3️⃣ Reading

Read the angle indicated on the scale. This is the angle of the slope in degrees. Record your measurement carefully.

Step-by-Step Guide to Using a Traditional Clinometer

Work in pairs - One person at the bottom of the slope with the clinometer, one at the top of the slope.
Measure eye height - The person at the bottom should measure their eye height.
Mark target height - The person at the top should mark or hold something at the same height as the first person's eyes.
Sight and align - The person at the bottom looks through the clinometer, aligning it with the marker at the top.
Read the angle - Note the reading shown on the scale (in degrees).
Repeat - Take at least three readings and calculate the average for accuracy.

Converting Between Measurement Units

Slope can be expressed in different ways:

Degrees (°) - Direct reading from the clinometer
Percentage (%) - Calculated as: tan(angle in degrees) × 100
Ratio - Expressed as 1:n where n = 100/percentage

Example: A slope of 10° equals approximately 17.6% or a ratio of 1:5.7

Recording and Interpreting Data

Proper data collection and interpretation are crucial for meaningful geographical analysis:

Creating a Data Collection Table

When measuring slopes in the field, use a table like this to record your findings:

Location	Reading 1 (°)	Reading 2 (°)	Reading 3 (°)	Average (°)	Slope % (calculated)	Notes
River bank A	12	13	12	12.3	21.8%	Stable vegetation cover
Hill slope B	25	24	26	25	46.6%	Signs of soil creep

Common Errors and How to Avoid Them

Even experienced geographers can make mistakes when using clinometers. Here are some common errors and how to avoid them:

⚠️ Not Sighting at Eye Level

Always ensure you're sighting at a point that's the same height as your eyes at the top of the slope. Sighting at the ground or above eye level will give incorrect readings.

⚠️ Unsteady Hands

Shaking can lead to inaccurate readings. Try to stabilise yourself by leaning against a tree or using a monopod. Take multiple readings and average them.

⚠️ Incorrect Distance

For very steep slopes, standing too close can make accurate sighting difficult. Move back to get a better angle if necessary, but remember to measure from your new position.

⚠️ Not Accounting for Vegetation

Dense vegetation can obscure the true slope. Try to find clear sightlines or measure in multiple locations to get representative data.

Practical Applications in Geographical Studies

Clinometer measurements are valuable in many geographical investigations:

🏠 Urban Studies

Measuring slope angles to understand urban development patterns and constraints on building.

🌊 River Studies

Measuring river valley cross-profiles and channel gradients to understand flow characteristics and erosion patterns.

🌲 Vegetation Studies

Correlating slope angle with vegetation types to understand aspect and drainage effects on plant communities.

Case Study Focus: River Long Profile Investigation

A common fieldwork investigation involves measuring the gradient of a river at different points along its course:

Select sampling points from source to mouth
At each point, use a clinometer to measure the gradient of the river channel
Plot the results on a graph showing distance from source against gradient
Analyse how gradient changes and correlates with other river characteristics like velocity, discharge and channel width

Students in the Lake District measured gradients along Styhead Gill and found that the gradient decreased from 15° near the source to 2° in the lower course, correlating with changes in sediment size and channel characteristics.

Making Your Own Clinometer

If you don't have access to a commercial clinometer, you can make your own with simple materials:

DIY Clinometer Instructions

Get a protractor, string, sticky tape, drinking straw and a small weight (like a washer or paper clip)
Attach the drinking straw along the straight edge of the protractor
Tie the string to the centre point of the protractor
Attach the weight to the free end of the string
The string will hang vertically due to gravity, indicating the angle on the protractor scale
Look through the straw to sight your target and read the angle where the string crosses the protractor scale

Note: Homemade clinometers are less accurate than professional ones but are perfectly suitable for basic fieldwork and understanding the principles involved.

Summary: Why Clinometers Matter in Geography

Clinometers are essential fieldwork tools that allow geographers to quantify the physical landscape. By measuring slopes accurately, you can:

Collect precise data for geographical analysis
Test geographical theories about landscape formation
Understand the relationship between slope and other geographical processes
Develop important fieldwork skills that are assessed in your iGCSE
Produce meaningful graphs and visual representations of landscapes

Remember that practice makes perfect with clinometer use. The more you use it in the field, the more accurate your readings will become!

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